1. Field of the Invention
The present invention generally relates to a high definition display unit and method, and more particularly relates to a television receiver having an electronic program guide (EPG) or pay-per-view (PPV) function which is further provided with an arrangement for selectively enabling/disabling image quality adjustment of EPG or PPV menu portions of a display to insure a viewability thereof.
2. Description of Related Art
Referring to FIG. 6, one type television receiver will be described for background purposes. More particularly, FIG. 6 is a schematic block circuit diagram showing a television receiver arrangement. In FIG. 6, an analog input signal I including an analog picture signal (hereinafter called a PI signal) corresponding to a television signal, is received by-an antenna 20 (or any other appropriate delivery mechanism, e.g., cable, infrared transmission, etc.). Such signal is then input to a demodulating circuit 3 via a tuner 1 and an IF circuit (not shown), passed through a decoder 5, and is ultimately processed in a video chroma processing circuit 7.
In addition, a portion P of information from the input signal is passed from the tuner I to a microprocessor M, and image information such as an EPG and/or pay-per-view (PPV) menus, that is, a service information (SI) signal in a form of a digital signal, is generated separately from the above PI signal by the microcomputer M or other separator arrangement. (The microprocessor also provides control signals to ones of the other illustrated components, such control signals not being further illustrated/described for sake of brevity and clarity of illustration/discussion.) Such SI signal is processed, amplified, and transmitted as an on-screen display signal. Therefore, with the FIG. 6 illustrated/described arrangement, a PI signal and an SI signal are demodulated separately.
The above separately demodulated PI signal and SI signal are superposed (e.g., added) with one another by a superposing section 10, are output to a display 11 via an output device 9, thus to be displayed. In the FIG. 6 television receiver, a quality of an image is adjusted by an image quality adjusting circuit 7a, e.g., within the video chroma processing circuit 7, using a user-variable adjustment part Ra. More particularly, a user adjusts with a control at a location before superposition by the superposing section 10, and therefore, the quality of the image and the quality of the image information (e.g., EPG and/or PPV) are completely independent from one another in this background arrangement, i.e., the user-variable adjustment of the display quality of the image does not affect the display quality of the image information owing to the fact that the image information is added to the image after the user-variable adjustment location.
In addition to the FIG. 6 arrangement, there are other methods for displaying an SI signal. For an on-screen circuit for displaying an SI signal, various methods are made practicable, i.e., there are a display character signal inserting circuit method of shunting a color output, and a method of a circuit and others for switching a Y input to a color output to an on-screen RGB and displaying an SI signal. Turning now to problems to be solved by the present invention, as a user cannot control an SI display in a system in which the above display of image information and the adjustment of the quality of an image are completely unrelated, there is a problem that an SI display may be rendered unreadable by luminance adjustment.
As further discussion, superposition of a PI signal and an SI signal in recent digital broadcasting corresponding television, for example, will be described. That is, the above PI signal and SI signal are mixed in a digital compression transmission mode such as in accordance with a Moving Picture Experts Group (MPEG) standard, and the mixed PI and SI signal is simultaneously transmitted or received via the antenna 20, is decoded by a digital decoder 4, the tuner I and the digital demodulating circuit 3, is processed by the video chroma processing circuit 7, is output and displayed. In this mode, the image quality is adjusted according to the above mixed signal by the video chroma processing circuit 7, i.e., both the PI and SI signal undergo image quality adjustment. There is a problem in this system in that an SI display may disappear or be rendered unreadable by the effect of the image quality adjusting circuit.
As digital broadcasting is tending to be increased in future, it is estimated that the control of SI information resulting in the disappearance of the SI display will be a more and more important problem.
The present invention is directed toward solving the problems in the above background art. More particularly, the object is to provide a high definition display unit which can prevent or limit a video chroma adjustment circuit from significantly adjusting an image quality of information image portions of a displayed image, such that an information image is never significantly degraded and/or rendered unviewable.
Numerous arrangements are possible for preventing or limiting such adjustment. More particularly, as one arrangement, a period in which the above both signals (i.e., PI and SI) are superposed is detected, and the image quality adjusting circuit is disabled according to the detection signal. In another arrangement, provided are a section for separating a picture information signal and a bypass circuit with respect to the video chroma processor, a superposed period of the above both signals (PI and SI) is detected, and the bypass circuit is operated according to the detection signal. In yet another arrangement, the superposed period of both signals (PI and SI) is detected and for the superposed period, the image quality adjusting circuit is adjusted according to level or value set according to a detection signal from a detector for detecting a brightness parameter. As a still further embodiment, the superposed period of the above both signals is detected, the image quality adjusting circuit is disabled for the superposed period, and an operating point of an output device is adjusted. Other arrangements are possible as disclosed within the detailed description ahead.
The foregoing and other objects, advantages, manner of operation, novel features and a better understanding of the present invention will become apparent from the following detailed description of the preferred embodiments and claims when read in connection with the accompanying drawings, all forming a part of the disclosure hereof this invention. While the foregoing and following written and illustrated disclosure focuses on disclosing embodiments of the invention which are considered preferred embodiments, it should be clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims.